The Census Bureau’s leader just stepped down just as it faces a huge funding crunch.

The Census Bureau now has no leader after John Thompson resigned from his position as director on Tuesday. His resignation comes at a critical time as the agency gears up to conduct the 2020 Census — and was already facing big funding problems.

The Census counts every person in the country, data that is used to allocate government resources to different states and localities, offer insight to businesses deciding on where to invest, and redraw congressional districts. The effects of unreliable or incomplete data could be devastating.

Thompson had been Census director since 2013 and had 27 years of previous experience working in the bureau before that. His term expired at the end of last year but he was given a one-year extension to oversee preparations for the 2020 Census. The kind of experience he brought to the job is considered critical as the bureau gets ready to conduct the count, which is done very ten years; in fact, a 2012 law required longer tenures for the director in an effort to ensure continuity and protect it from political interference.

The Trump administration hasn’t announced a successor yet, and now it will have to act quickly to fill the leadership vacuum — which could be difficult, as there aren’t many experienced candidates lined up to step in. A spokesperson for the Commerce Department, which houses the bureau, told the Washington Post an acting director will be installed “in the coming days” and a permanent leader will be found “in due course.”

Thompson’s departure comes as the bureau faces the question of whether it can successfully conduct its count in three years with few resources. Congress has already mandated that the 2020 Census cost no more than the $12.5 billion price tag of the last one conducted in 2010, despite the fact that inflation, population growth, and technology challenges will almost certainly make the task more costly this time.

The bureau also typically gets an infusion of funding in the three years before a Census so that it can adequately prepare by testing its methods, hiring Census takers, and publicizing the count so people participate. It is in particular need of funding for testing right now given that it has decided to shift to a more technology-focused approach to save money, but has to ensure that those systems will actually work in 2020.

But that infusion hasn’t come yet. Congress only approved $1.47 billion for this fiscal year, lower than its request of $1.6 billion, and Trump’s budget outline only allocated $1.5 billion for next year. That amounts to keeping funding flat when, according to past experience, its budget should be increased by 60 percent or more.

If the bureau doesn’t get that money, it could be “catastrophic” for the 2020 Census, according to Terri Ann Lowenthal, a former staff director of the House census oversight subcommittee, who also warned that as things stand the bureau won’t be able to afford its “dress rehearsal” next year.

Some are now worried that the lack of a director will throw off an already faltering operation even further. “Without strong leadership at the bureau, this vital mission will be imperiled,” Rep. José Serrano (D-NY) told the Washington Post.